The aim of this application is to characterize specific aspects of the biology of basic fibroblast growth factor (bFGF). Basic FGF interacts with heparan sulfate. We have hypothesized that this interaction forms a complex which is the biologically relevant form of bFGF. We hypothesize that when complexed to heparan sulfate, bFGF is resistant to proteolytic and thermal denaturation, has increased solubility and is an functionally active as fee bFGF. Experiments will be performed to test these ideas. Basic FGF binds to alpha 2 macroglobulin (alpha2M). We shall charactrize the nature of this complex. The rate of formation, its biological activities as well as its possible role in the regulation of extracellular bFGF levels. Finally, we whall test the role of bFGF in development. Female guinea pigs will be immunized, bread, and the offspring examined for developmental abnormalities. Passive immunization and monoclonal antibodies may also used in addition to natural immunization.